718 DR. C. I. rORSTTH MAJOR ON THE [ June 1 , 



ment than with the molars of Cercopithecidae, which "Winge himself 

 declares to be anything but primitive '. 



As the same author considers the Muridse to be a terminal 

 group- — and in this I certainly agree with him — I cannot see how 

 we \\ould have to explain the sudden appearance in them of 

 a primitive molar form (that of Cricetus, according to Winge). 

 All tlie other " Oricetini," in their more complicated molars, come 

 nearer to the " Aiwinaluruhi' " than does Cricetus. Pseudosciurus 

 and Sciuroides are considered by "Winge himself to be the most 

 primitive amongst Anomrduridce. Now the mesial " transverse 

 ridge " is present in Scmroides as well as in Trechomys, &c,, 

 although in the molars of the former it does not reach so far 

 inwards (in upper molars) or outwards (in lower molars) as it 

 does in TrecJiomys ^. 



Summary. 



The Malagasy Muridce have, by common accord, been placed 

 amongst the " Oricetina^ " ( " Sigmodontince " ) ; this is true in a 

 general sense, at least with regard to the great majority of them. 



In the foregoing pages I have tried to define more precisely 

 their position, as well as their relationships with Min-idce from 

 other regions. Although the present paper deals essentially only 

 with one genus, and though it will be necessary for me to take 

 the Malagasy Eodents (forming, as I consider, a special subfamily, 

 the Nesomyinoi) up again as a whole, when all the forms will have 

 been fully worked out, I could not, for comparison's sake, avoid 

 anticipating somewhat the future publication, by throwing side- 

 glances on some of the other genera. 



The Malagasy Eodents have to be considered as the lowest of 

 the Marida — lower even than the Miocene members of the family, 

 so far as these are known, — because in cranial and dental 

 characters they approach more than any other Muridce such more 

 primitive groups of Eodentia as the Dipodidce and Winge's 

 Anomaluridce. These characters are : large hafraorbital foramen 

 — well-developed jngale — absence of advanced hypselodontism — 

 intermediate cusps of molars less reduced than in Hesperoimjince 

 and in Old World Criceiince, and external cusps (of upper molars) 

 less reduced than in the Mwrince — greater agreement hi pattern and 

 size of m. 1 and m. 2 than in other Muridce ; very often all three 

 molars agree with each other. 



If I had to regret that in my excavations I came upon but scanty 

 remains of extinct fossil Mammalia, I have had some compensa- 

 tion by these living fossils. Were any justification necessary for 

 having divided my time between neontological and palseonto- 

 logical exploration, this result would amply justify my proceeding. 



1 ' Jortlfundne og nulevencle Aber (Primates) fra Lagoa Santa, &c.,' Kjo- 

 benhavn, 1895 (" E Museo Lundii"), p. 40. " Hvis Simiinernes Kindtsender 

 vare fremkomne af Tcender saa lidt oprindelig f-om hos Cercopitheciner . . .'' 

 (The italics are mine.) 



- The comparison of the molars of Sciuroides with those of PseJidosciurua 

 shows that the outer termination (in upper molars) of this " transverse ridge " 

 is nothing but the ancient outer cusp, 2, of Pseudosciurus. 



